2162821 has 2 divisors, whose sum is σ = 2162822. Its totient is φ = 2162820.

The previous prime is 2162813. The next prime is 2162843. The reversal of 2162821 is 1282612.

It is an a-pointer prime, because the next prime (2162843) can be obtained adding 2162821 to its sum of digits (22).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2117025 + 45796 = 1455^2 + 214^2 .

It is a cyclic number.

It is not a de Polignac number, because 2162821 - 2³ = 2162813 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2162792 and 2162801.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2162221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1081410 + 1081411.

It is an arithmetic number, because the mean of its divisors is an integer number (1081411).

2^2162821 is an apocalyptic number.

It is an amenable number.

2162821 is a deficient number, since it is larger than the sum of its proper divisors (1).

2162821 is an equidigital number, since it uses as much as digits as its factorization.

2162821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 384, while the sum is 22.

The square root of 2162821 is about 1470.6532562096. The cubic root of 2162821 is about 129.3223315531.

The spelling of 2162821 in words is "two million, one hundred sixty-two thousand, eight hundred twenty-one".